[PATCH v3 4/6] drm/i915/alpm: Add compute config for lobf

[Hogander, Jouni]

On Thu, 2024-04-25 at 00:08 +0530, Animesh Manna wrote:
> Link Off Between Active Frames, is a new feature for eDP
> that allows the panel to go to lower power state after
> transmission of data. This is a feature on top of ALPM, AS SDP.
> Add compute config during atomic-check phase.
> 
> v1: RFC version.
> v2: Add separate flag for auxless-alpm. [Jani]
> v3:
> - intel_dp->lobf_supported replaced with crtc_state->has_lobf.
> [Jouni]
> - Add DISPLAY_VER() check. [Jouni]
> - Modify function name of get_aux_less_status. [Jani]
> 
> Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_alpm.c     | 48
> +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_alpm.h     |  5 ++
>  .../drm/i915/display/intel_display_types.h    |  4 ++
>  drivers/gpu/drm/i915/display/intel_dp.c       |  4 ++
>  4 files changed, 61 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> b/drivers/gpu/drm/i915/display/intel_alpm.c
> index 13bac3e8c8fa..3bb69ed16aab 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> @@ -11,6 +11,16 @@
>  #include "intel_dp_aux.h"
>  #include "intel_psr_regs.h"
>  
> +bool intel_alpm_get_aux_less_status(struct intel_dp *intel_dp)
> +{
> +       u8 alpm_caps = 0;
> +
> +       if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP,
> +                             &alpm_caps) != 1)
> +               return false;
> +       return alpm_caps & DP_ALPM_AUX_LESS_CAP;
> +}
> +
>  /*
>   * See Bspec: 71632 for the table
>   *
> @@ -242,6 +252,44 @@ bool intel_alpm_compute_params(struct intel_dp
> *intel_dp,
>         return true;
>  }
>  
> +void intel_alpm_compute_lobf_config(struct intel_dp *intel_dp,
> +                                   struct intel_crtc_state
> *crtc_state,
> +                                   struct drm_connector_state
> *conn_state)
> +{
> +       struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +       struct drm_display_mode *adjusted_mode = &crtc_state-
> >hw.adjusted_mode;
> +       int waketime_in_lines, first_sdp_position;
> +       int context_latency, guardband;
> +
> +       crtc_state->has_lobf = false;

Drop this line. I think crtc_state is reset before doing this
compute_config

> +
> +       if (!intel_dp_is_edp(intel_dp))
> +               return;
> +
> +       if (DISPLAY_VER(i915) < 20)
> +               return;
> +
> +       if (!intel_dp_as_sdp_supported(intel_dp))
> +               return;
> +
> +       if (crtc_state->has_psr)
> +               return;
> +
> +       if (intel_alpm_compute_params(intel_dp, crtc_state)) {

I think it is easier to read and helps avoiding big if blocks if you:

if (!intel_alpm_compute_params(intel_dp, crtc_state())
    return;

This actually brings up another thing: do we want to spread intel_psr.c
pollution by continue using these boolean return values? I would prefer
changing intel_alpm_compute_params return value to "normal" int
approach and return 0 on success. This would mean one more patch
changing it.

> +               context_latency = adjusted_mode->crtc_vblank_start -
> adjusted_mode->crtc_vdisplay;
> +               guardband = adjusted_mode->crtc_vtotal -
> +                           adjusted_mode->crtc_vdisplay -
> context_latency;
> +               first_sdp_position = adjusted_mode->crtc_vtotal -
> adjusted_mode->crtc_vsync_start;
> +               if (intel_dp->alpm_parameters.auxless_alpm_supported)
> +                       waketime_in_lines = intel_dp-
> >alpm_parameters.io_wake_lines;
> +               else
> +                       waketime_in_lines = intel_dp-
> >alpm_parameters.fast_wake_lines;
> +
> +               if ((context_latency + guardband) >
> (first_sdp_position + waketime_in_lines))
> +                       crtc_state->has_lobf = true;

crtc_state->has_lobf = (context_latency + guardband) >
(first_sdp_position + waketime_in_lines);

> +       }
> +}
> +
>  static void lnl_alpm_configure(struct intel_dp *intel_dp)
>  {
>         struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> diff --git a/drivers/gpu/drm/i915/display/intel_alpm.h
> b/drivers/gpu/drm/i915/display/intel_alpm.h
> index c45d078e5a6b..b9602b71d28f 100644
> --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> @@ -10,9 +10,14 @@
>  
>  struct intel_dp;
>  struct intel_crtc_state;
> +struct drm_connector_state;
>  
> +bool intel_alpm_get_aux_less_status(struct intel_dp *intel_dp);
>  bool intel_alpm_compute_params(struct intel_dp *intel_dp,
>                                struct intel_crtc_state *crtc_state);
> +void intel_alpm_compute_lobf_config(struct intel_dp *intel_dp,
> +                                   struct intel_crtc_state
> *crtc_state,
> +                                   struct drm_connector_state
> *conn_state);
>  void intel_alpm_configure(struct intel_dp *intel_dp);
>  
>  #endif
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index d94f50c6dc6c..5a0ffd5aa48b 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1405,6 +1405,9 @@ struct intel_crtc_state {
>  
>         /* for loading single buffered registers during vblank */
>         struct drm_vblank_work vblank_work;
> +
> +       /* LOBF flag */
> +       bool has_lobf;
>  };
>  
>  enum intel_pipe_crc_source {
> @@ -1835,6 +1838,7 @@ struct intel_dp {
>                 u8 fast_wake_lines;
>  
>                 /* LNL and beyond */
> +               bool auxless_alpm_supported;
>                 u8 check_entry_lines;
>                 u8 silence_period_sym_clocks;
>                 u8 lfps_half_cycle_num_of_syms;
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index e05e25cd4a94..563739c6014c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -48,6 +48,7 @@
>  #include "i915_drv.h"
>  #include "i915_irq.h"
>  #include "i915_reg.h"
> +#include "intel_alpm.h"
>  #include "intel_atomic.h"
>  #include "intel_audio.h"
>  #include "intel_backlight.h"
> @@ -2997,6 +2998,7 @@ intel_dp_compute_config(struct intel_encoder
> *encoder,
>         intel_vrr_compute_config(pipe_config, conn_state);
>         intel_dp_compute_as_sdp(intel_dp, pipe_config);
>         intel_psr_compute_config(intel_dp, pipe_config, conn_state);
> +       intel_alpm_compute_lobf_config(intel_dp, pipe_config,
> conn_state);
>         intel_dp_drrs_compute_config(connector, pipe_config,
> link_bpp_x16);
>         intel_dp_compute_vsc_sdp(intel_dp, pipe_config, conn_state);
>         intel_dp_compute_hdr_metadata_infoframe_sdp(intel_dp,
> pipe_config, conn_state);
> @@ -6612,6 +6614,8 @@ static bool intel_edp_init_connector(struct
> intel_dp *intel_dp,
>  
>         intel_pps_init_late(intel_dp);
>  
> +       intel_dp->alpm_parameters.auxless_alpm_supported =
> intel_alpm_get_aux_less_status(intel_dp);

How about aux_wake ?

> +
>         return true;
>  
>  out_vdd_off: